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Unmanned Ground Vehicle Proximal Sensing For Forage Biomass Production Estimations, Curtis Erwin

All Theses

A large increase in productivity could be realized by small increases in efficiency and utilization on grasslands due to their large area. Pre-harvest biomass estimations can help forage producers make better informed management decisions. Producers of dry hay and hay silage can better identify plant growth stages and the optimal time to harvest. Grazers can better determine the most efficient number of animals and stocking density. The goal of this study was to create a novel pre-harvest biomass estimation method utilizing compressed height combined with an unmanned ground vehicle (UGV). A compression plate named a “compression ski” was constructed and …

Nitrogen Use Efficiency Of Pretassel Nitrogen Applications In Corn, Robyn Brittlee Mulloy

Graduate Theses and Dissertations

Corn (Zea mays L.) production continues to be a critical component of row-crop production systems within Arkansas and is seeing a resurgence in recent years. Nitrogen (N) is critical for corn growth and is often one of the single largest input costs associated with corn production. Research objectives for this study were to determine the nitrogen use efficiency (NUE) of late season N applications as influenced by sidedress N rate and timing of pretassel application and to quantify the nutrient uptake and partitioning in modern era corn hybrids within a furrow-irrigated production system. Research was conducted at the Milo J. …

Nitrogen Management In Rice Under Suboptimal Soil Conditions, Payton Suzanne Rhea

Graduate Theses and Dissertations

In Mid-South rice (Oryza sativa, L.) production, nitrogen (N) fertilizer management for pureline varieties is most often recommended as a single preflood (SPF) or two-way split (2WS) application in a direct-seeded, delayed-flood system. Most of the N fertilizer is typically applied at the four- to six-leaf stage onto dry soil, and the second application, if necessary, into the floodwater during early reproductive growth stages (referred to as midseason). Environmental factors frequently prohibit growers from applying early N fertilizer under optimal dry soil conditions. A study was conducted to determine the best N fertilization management practices to utilize in rice when …

Sustainability And Health Impacts Of Pulse Crops In The United States Using Life Cycle Assessment, Prathamesh A. Bandekar

Graduate Theses and Dissertations

Environmental sustainability and human health impact of pulses produced and consumed in the United States was assessed using life cycle assessment (LCA). The study included three objectives 1) to estimate environmental impact of current production and consumption practices in the United States using attributional LCA; 2) to estimate environmental and human health impact of iso-caloric diets containing varying amounts of pulses using Hybrid-LCA and Combined Nutritional and Environmental-LCA (CONE-LCA); and 3) to estimate environmental impact of increased demand for pulses using consequential LCA. Scope of the study varied for each objective with system boundary encompassing cradle-to-grave activities for objective 1 …

Applying A Material Science Approach To Improve Rice Processing Performance, Michelle Oppong Siaw

Graduate Theses and Dissertations

Rice is typically consumed as whole kernel, which makes the economic value of whole kernels twice that of brokens. Macro-structural defects such as fissures and chalkiness have been recognized to weaken kernel mechanical strength, and thereby increase breakage during milling. However, high percentages of brokens are sometimes recorded even though these defects are controlled prior to milling. It was hypothesized that rice milling characteristics are influenced by endosperm porosity from the structural arrangement of chemical components and by bran thickness and composition. Thus, this study aimed to modify chemical components by applying treatments to alter rice porosity and its associated …

Food Security & Urban Agriculture - Considerations For Soil Improvements And Crop Planning, Aaron Sedivy

Doctor of Plant Health Program: Dissertations and Student Research

Urban agriculture provides many benefits, such as energy conservation, rainwater remediation, increased aesthetic and property value, and therapeutic use for physical, cognitive, and emotional wellbeing. Urban agriculture can also provide critical integrity to each pillar of food security: availability, access, utilization, and stability. As urban agricultural activities increase, social interactions will follow in concert. This will provide opportunities for building trust through the two-way communication of contrasting perspectives, cultures, and beliefs using impartial narratives. Growers can use knowledge and understanding gained from these positive social interactions to formulate their personal paradigms for practice and better meet the needs of each …

Comparative Genomics Of Five Valsa Species Gives Insights On Their Pathogenicity Evolution, Guangchao Sun, Shichang Xie, Lin Tang, Chao Zhao, Mian Zhang, Lili Huang

Department of Agronomy and Horticulture: Faculty Publications

Valsa is a genus of ascomycetes within the Valsaceae family. This family includes many wood destructive pathogens such as the well known Valsa mali and Valsa pyri which cause canker diseases in fruit trees and threaten the global fruit production. Lack of genomic information of this family is impeding our understandings about their evolution and genetic basis of their pathogenicity divergence. Here, we report genome assemblies of Valsa malicola, Valsa persoonii, and Valsa sordida which represent close relatives of Valsa mali and Valsa pyri with different host preferences. Comparative genomics analysis revealed that segmental rearrangements, inversions, and translocations …

Approaches To Supplementing Silicon In Soilless Media And The Value Of Silicon In The Mitigation Of Drought Stress, Mackenzie Grace Dey

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Silicon (Si) is not considered an essential element for plants to complete their lifecycle, but is known to be beneficial for plants under environmental stress such as drought. Unlike natural soils, Si is minimally bioavailable in soilless media. With indoor agriculture and greenhouse production increasing, the benefits of Si have been seen and Si should be supplemented. This work aimed to characterize and quantify the dissolution of Si from media substrates and additives to achieve a steady-state release of Si in soilless media. Typical media components such as coconut coir, peat moss, perlite, rock wool, sand, and vermiculite minimally released …

Influence Of Pretreatments On Physiological Status And Post-Planting Survival Of Thornforest Seedlings In A Restoration Context, Douglas E. Mainhart

Theses and Dissertations

Semi-arid ecosystems across the globe have faced land conversion posing a threat to the important ecosystem services they provide. Revegetation-centered restoration efforts in arid regions have low success due to limited water availability and higher temperatures. Typically, practitioners utilize methods that modify field conditions around seedlings to mitigate these stressors. I evaluated the efficacy of in-nursery treatments to improve plant water status. Three pretreatments were applied: elevated CO2, drought hardening, and an antitranspirant foliar spray. My goal was to understand how these pretreatments would impact survival and growth in the field and what physiological traits they altered. Elevated CO2 and …

Comparative Genome Analysis Of Plant Ascomycete Fungal Pathogens With Different Lifestyles Reveals Distinctive Virulence Strategies, Yansu Wang, Jie Wu, Jiacheng Yan, Ming Guo, Lei Xu, Liping Hou, Quan Zou

Department of Agronomy and Horticulture: Faculty Publications

Background: Pathogens have evolved diverse lifestyles and adopted pivotal new roles in both natural ecosystems and human environments. However, the molecular mechanisms underlying their adaptation to new lifestyles are obscure. Comparative genomics was adopted to determine distinct strategies of plant ascomycete fungal pathogens with different lifestyles and to elucidate their distinctive virulence strategies. Results: We found that plant ascomycete biotrophs exhibited lower gene gain and loss events and loss of CAZyme-encoding genes involved in plant cell wall degradation and biosynthesis gene clusters for the production of secondary metabolites in the genome. Comparison with the candidate effectome detected distinctive variations between …

Exploring Soil-Tree Interactions After Applying Organic Matter Amendments To Peach Orchards In The Subtropical Climate Of The Southeastern United States, Brian Lawrence

All Dissertations

Soil disturbance from the cultivation and intensive management of orchards in hot and humid subtropical climates can reduce soil organic matter (OM). This research explored how the addition of OM amendments impact soil and tree parameters in two field studies and how proximity to OM may elicit unique genomic response of peach roots in a split-root pot study. The first field study applied two rates of compost (1x and 2x) and subsequently reduced fertilizer applications annually to a virgin and replant orchard location. While both compost rates successfully replaced fertilizers, only the 2x rate in the replant location increased soil …

Insights On The Behavior Of Nano-Copper In The Agroecosystem: Mycorrhizal Associations With Spearmint (Mentha Spicata), Suzanne Annette Apodaca

Open Access Theses & Dissertations

Nanotechnology offers significant potential benefits to our society, including the agriculture sector. With the advancement of nano-enabled agrochemicals towards sustainable and efficient agricultural practices, it is essential to address environmental issues associated with the use of nanoscale materials. The same properties that give promise to applications of nanotechnology in modern agriculture could have unintended consequences on ecosystem dynamics. A point of concern for risk management is the impact of engineered nanomaterials (ENMs) to beneficial microbial communities, which support a variety of ecosystem services.

Use of copper (Cu) products in agriculture are based on their abundance, role as a micronutrient, and …

Diagnosing Excess Nitrogen In Rice Using Post-Season Tissue Samples, Kyle Hoegenauer

Graduate Theses and Dissertations

Proper nitrogen (N) management in rice production can be difficult to achieve without the aid of tools such as soil and tissue tests. There are no tests currently available to rice producers that determine whether N has been managed properly throughout the season or that detect instances of over fertilization. Rice stalk samples were collected from N response trials within 3 days of harvest from the primary Arkansas rice growing region in 2016-2018. Stalk samples were analyzed for N concentration through a KCl extraction and spectrofluorometric quantification. Samples analyzed with leaf material intact contained statistically different N concentrations than samples …

Micronutrient Concentration Effects On Lettuce Growth And Susceptibility To Pythium, Kalyn M. Helms

Graduate Theses and Dissertations

In hydroponic production waterborne pathogens such as Pythium are ubiquitous and continually threaten a wide range of Controlled Environment Agriculture (CEA) crops in hydroponic production, including but not limited to: lettuce, spinach, basil, arugula, cucumber, tomato, sweet pepper, roses, chrysanthemums, and cannabis (Sutton et al., 2006; Gull, 2002; McGehee and Raudales, 2021; Gillespie, 2020). Despite extensive sanitation measures, disease control in hydroponics is fallible and requires constant surveillance and management to minimize outbreaks (Sutton et al., 2006). A potential disease suppression strategy is to increase micronutrient concentrations within hydroponic systems to naturally strengthen plant defenses against pathogens such as Pythium. …

In-Field And Greenhouse Assessments Of A Selection Of Preemergent Herbicides On Newly Planted Blackberries, Kayla Knepp

Graduate Theses and Dissertations

This field trial assesses some of the preemergence herbicide options available to growers and their effect on newly transplanted blackberries (Rubus L. subgenus Rubus Watson). Weed control has recently been surveyed as a top priority for blackberry growers; however, limited preemergence herbicides are registered for new blackberry plantings. Weed control is an ongoing component of blackberry production and with few in-season postemergence herbicide options available, growers rely on preemergence herbicides to maintain clean fields. The preemergent herbicides assessed in this trial were chosen with the intention to broaden the chemical control options available to growers in new plantings. A two-year …

Comparative Metabolites Profiling Of Sesamum Indicum Seeds In Context Of Their Origin, Processing And Biological Activity Using Bioinformatics Tools, Bishoy Fayez Abib

Theses and Dissertations

Sesame (Sesamum indicum), is a significant oilseed crop with great economical and nutritional value, encompassing a plethora of primary and secondary metabolites that exhibit pharmacological and therapeutic merits. The present study, using untargeted comparative metabolomics, aims to authenticate and classify sesame seed accessions from different countries of origin i.e., Egypt, Sudan and Nigeria, based on their metabolite variations and in relation to their biological activity and nutritional value such as mineral content. Also, to further assess the impact of processing on sesame’s nutritional value and biological activity using the industrial production of sesame paste as a case study. To achieve …

Bison Movements Change With Weather: Implications For Their Continued Conservation In The Anthropocene, Nicholas A. Mcmillan, Samuel D. Fuhlendorf, Barney Luttbeg, Laura E. Goodman, Craig A. Davis, Brady W. Allred, Robert G. Hamilton

Department of Agronomy and Horticulture: Faculty Publications

Animal movement patterns are affected by complex interactions between biotic and abiotic landscape conditions, and these patterns are being altered by weather variability associated with a changing climate. Some animals, like the American plains bison (Bison bison L.; hereafter, plains bison), are considered keystone species, thus their response to weather variability may alter ecosystem structure and biodiversity patterns. Many movement studies of plains bison and other ungulates have focused on point-pattern analyses (e.g., resource-selection) that have provided information about where these animals move, but information about when or why these animals move is limited. For example, information surrounding the …

The Genome Of Orychophragmus Violaceus Provides Genomic Insights Into The Evolution Of Brassicaceaepolyploidizationandits Distinct Traits, Kang Zhang, Yinqing Yang, Xin Zhang, Lingkui Zhang, Yu Fu, Zhongwei Guo, Shumin Chen, Jian Wu, James C. Schnable, Keke Yi, Xiaowu Wang, Feng Cheng

Department of Agronomy and Horticulture: Faculty Publications

Orychophragmus violaceus, referred to as ‘‘eryuelan’’ (February orchid) in China, is an early-flowering ornamental plant. The high oil content and abundance of unsaturated fatty acids in O. violaceus seeds make it a potential high-quality oilseed crop. Here, we generated a whole-genome assembly for O. violaceus using Nanopore and Hi-C sequencing technologies. The assembled genome of O. violaceus was ~1.3 Gb in size, with 12 pairs of chromosomes. Through investigation of ancestral genome evolution, we determined that the genome of O. violaceus experienced a tetraploidization event from a diploid progenitor with the translocated proto-Calepineae karyotype. Comparisons between the reconstructed subgenomes …

Range-Based Livestock Production In Turkmenistan, R. H. Behnke, G. Davidson

IGC Proceedings (1977-2023)

Turkmenistan retains a centralized system of livestock production in which many critical assets are owned by the state. Though technically in the temperate zone, the country's climate is harsh and unstable. Groundwater resources are unevenly distributed, leaving many potential grazing areas seasonally inaccessible due to lack of drinking water for livestock. This paper summarizes the results of a three-year study of rangelands, livestock production, flock economics and land tenure at two study sites, one in central and the other in eastern Turkmenistan. The results of this study suggest that pastoral communities in Turkmenistan have coped remarkably well with the institutional …

Characterization Of Algerian Apricots (Prunus Armeniaca) Using Morphological And Pomological Markers, Kaouther Boutiti, Ines Bellil, Douadi Khelifi

Karbala International Journal of Modern Science

The aim of this study was to evaluate the diversity of an Algerian apricot germplasm. This Algerian apricot was characterized by a green-yellow skin, a red ground color, and a light orange flesh color in general. Besides, highly positive and negative significant correlations were revealed between the studied characters. Whereby, the principal component analysis explained 81% of the variability. Fruit, stone and leaves dimensions were the main features that explained evidentially the majority of variability. Moreover, the cluster analysis divided the accessions into two major groups. Thus, Algerian accessions selected in this study may have the potential to be used …

Population Genomic Characterization Of Cercospora Janseana On Rice In The Southern United States, Jacob Searight

LSU Master's Theses

Cercospora janseana is the causative agent of narrow brown leaf spot (NBLS). Effort had been undertaken since the 1940’s to control this disease through resistance breeding in the Southern United States. However, a severe epidemic of NBLS in 2006 inspired renewed focus on managing this disease. One tool for managing this disease has been identified among resistant cultivars, the CRSP-2.1 resistance locus to NBLS. One thing limiting the investment and deployment of CRSP-2.1, and other unknown resistance genes, is the historical observation that resistance to NBLS rapidly breaks-down in the field. Together, the rapid breakdown of resistance to NBLS …

Assessment Of Nitrogen Nutrition Status Of Grasses Under Water Deficit And Recovery, V. G. Dugo, Jean-Louis Durand, F. Gastal

IGC Proceedings (1977-2023)

Grasslands are rarely irrigated. They are therefore systematically submitted to more or less severe water deficits: as well as mineral deficiencies, water scarcity often also results in a reduction of nitrogen (N) status. Although identified some time ago, qualitatively, the interaction with N still remains difficult to take into account in quantitative analyses of crop physiology under water deficits. This paper illustrates how the nitrogen (N) status of the crop changes under water deficits. A N nutrition index (INN) was defined as the ratio of the actual N concentration of forage with the theoretical N concentration under optimal conditions, the …

Diet Effects On Dairy Manure Nitrogen Excretion And Cycling, J. M. Powell, T. H. Misselbrook

IGC Proceedings (1977-2023)

The amount and forms of (nitrogen) N excreted by ruminant livestock and post excretion manure N cycling are highly influenced by what is fed. For example, the relative amount of urinary N, faecal endogenous N of microbial and gut origin, and faecal undigested feed N is affected by how much dietary fibre and secondary compounds (e.g., tannins, polyphneolics) are consumed. Each manure N component has a different propensity for loss; for example via ammonia (NH3) volatilisation (Misselbrook et al., 2004), leaching, and cycles differently in the soil-plant continuum (Powell, 2003). We evaluated dairy diet effects on amount and forms …

Benomyl Effects On Plant Productivity Through Arbuscular Mycorrhiza Restriction In A Greek Upland Grassland, M. Orfanoudakis, A. P. Mamolos, F. Karanika, D. S. Veresoglou

IGC Proceedings (1977-2023)

Interactions between plants and microbes are important for plant community structure. Many plants establish symbioses with arbuscular mycorrhizal (AM) fungi, which play a central role in soil fertility, plant nutrition and the maintenance of stability and biodiversity within plant communities by improving uptake of nutrients and water. AM fungi can improve growth/performance in a variety of plant species by influencing intra- and interspecific competition of neighbouring plants and thus regulate coexistence and diversity in mixed communities. The aim was to study AMF effects on plant productivity and diversity in Greek upland grasslands.

Integrating Below-Ground Ecology Into Sustainable Grassland Management, R. D. Bardgett

IGC Proceedings (1977-2023)

Key points

1. Grasslands produce soils that sustain an abundant and diverse soil food web, providing tremendous opportunity for below-ground interactions to influence nutrient cycling processes and plant production.

2. Fast developing areas of ecological science offer scope to harness positive outcomes of below-ground ecology for enhancing efficient cycling of nutrients in sustainable grassland systems.

Chemical Components And Effects On Soil Quality In Temperate Grazed Pasture Systems, M. H. Beare, D. Curtin, S. Thomas, P. M. Fraser, G. S. Francis

IGC Proceedings (1977-2023)

Key points

1. Legume/grass pastures retain feedbacks on N supply that may help to reduce losses of N to the wider environment.

2. Intensive use of N fertilisers tends to increase SOM turnover and increase losses of N to the environment.

3. Increased use of fertilisers has contributed little to soil organic matter storage in grazed pastoral systems.

Physical Constraints In Grassland Ecosystems, I. M. Young, K. Ritz, C. S. Sturrock, R. Heck

IGC Proceedings (1977-2023)

Key points

1. Grassland system management must account adequately for biophysical and biochemical processes.

2. Amenity turf, especially sports turf, provides an excellent case study on how biology and physics interact to impact on the functioning of a grass ecosystem.

3. Microorganisms produce hydrophobic compounds that act to decrease water ingress and alter the function of the soil-grass ecosystem.

Improved Livelihoods From Grasslands; The Case Of Napier Grass In Smallholder Dairy Farms In Kenya, David Miano Mwangi, D. Romney, S. Staal, I. Baltenweck, S. Mwendia

IGC Proceedings (1977-2023)

In Kenya, smallholder farmers produce about 80% of the marketed milk. The farming systems vary from mixed farms with up to 10 ha of land and < 10 dairy cows (Gitau et al., 1994; Anon., 1985), to intensive smallholder dairy producers in the high human population central Kenya region with 0.9 to 2 ha of land and 3-4 dairy cows (Staal et al., 2001a). Milk production depends heavily on the cultivation of forages, with Pennisetum purpureum (Napier grass) by far the most important. An estimated 350,000 of the 600,000 smallholder farms in Kenya grow and utilize P. purpureum on their farms.

There are …

Computer-Based Forage Management Tools: Historical, Current, And Future Applications, David B. Hannaway, C. Daly, D. F. Chapman, B. B. Baker, A. S. Cooper

IGC Proceedings (1977-2023)

Forage management has been an important human activity since the beginning of civilization. By comparison, the personal computer has been available only in the immediate past. The software developed to deal with the complexity of climate, soil, plant, animal, and socioeconomic factors has seen huge changes in a few decades. Mainframe computers facilitated numerical calculations for exploring relationships among dozens of variables. Personal computers opened the door for more individual scientist creativity and routine communication. Web-based communication globalised the option for multidisciplinary teams to tackle problems. Forage-related computer applications abound, allowing farmers, ranchers, and others to more effectively manage the …

Paying For Our Keep: Grasslands Decision Support In More-Developed Countries, Andrew D. Moore

IGC Proceedings (1977-2023)

“Models in grassland science have come to stay, and so they must be made to pay for their keep. To do that, it will be necessary to improve their scientific sophistication and their management relevance...” (Seligman, 1993).

Decision support (DS) tools in grassland agriculture have also come to stay. This review will examine the ways and means by which DS tools are being made to pay for their keep, with a focus upon DS efforts from the last decade and on the lessons that arise for those who develop DS tools for grasslands. A survey of the present state of …